Dialysis catheter
From Wikipedia, the free encyclopedia
A dialysis catheter is a catheter used for exchanging blood to and from a hemodialysis machine and a patient.
![Thumb image](http://upload.wikimedia.org/wikipedia/commons/thumb/4/44/Catheter.png/200px-Catheter.png)
The dialysis catheter contains two lumens: venous and arterial. Although both lumens are in the vein, the "arterial" lumen, like natural arteries, carries blood away from the heart, while the "venous" lumen returns blood towards the heart. The arterial lumen (typically red) withdraws blood from the patient and carries it to the dialysis machine, while the venous lumen (typically blue) returns blood to the patient (from the dialysis machine). Flow rates of dialysis catheters range between 200 and 500 ml/min.
If a patient requires long-term dialysis therapy, a chronic dialysis catheter will be inserted. Chronic catheters contain a dacron cuff that is tunneled beneath the skin approximately 3–8 cm. The tunnel is thought to add a barrier to infection. The most popular dialysis catheter sold on the market today is the Symmetrical-Tip dialysis catheter. This catheter is in the form spiral Z shape.
![Thumb image](http://upload.wikimedia.org/wikipedia/commons/thumb/2/20/Permacath.jpg/640px-Permacath.jpg)